1. Field of the Invention.
This invention relates to connectors in general and in particular to seismic connectors which can be single ended or double ended.
2. Description of the Prior Art.
This invention relates to the geophone stringing art and, more particularly, to a hybrid seismic takeout connector, known in the art as a "hybrid clip" which is adapted to connect two conductors from a geophone leader cable to two male and female contacts of the clip, and then to interconnect several such clips together in various series and parallel combinations.
This is necessary because in seismic prospecting, a plurality of geophone strings is normally required for each channel of data to be recorded, and a means must be provided for electrically interconnecting together this plurality of strings. On each string, the geophones are spaced along and are electrically connected by suitable means to the leader cable. Each such string has one or more hybrid clips installed on the geophone leader termination. The leader cable of the hybrid clip electrically connects the geophone strings to one or more two-wire takeout connectors on the spread cable.
Currently it is a common practice to use only two conductors for connecting strings of geophones to a single takeout connector on the spread cable for a particular channel forming part of the seismic recording instruments. Since it is preferred that the spread cable be provided with only one two-wire takeout for each seismic data recording channel, it is necessary to electrically interconnect in parallel and/or in series the geophone strings to form a geophone group that will be used for each channel, and then to connect the group thus formed to the corresponding takeout connector on the spread cable for that particular channel.
U.S. Pat. No. 3,907,393 describes a hybrid takeout clip for interconnecting groups of such geophone strings, and also describes the art prior to the invention claimed in said patent. This patented hybrid clip has rapidly met with considerable commercial success primarily because of its quick connect and disconnect characteristics and because it combines several desirable functions previously performed by single-ended connectors and by T-couplers.
It was found, however, that when the exposed contacts of the patented hybrid clip touch the earth or when they become exposed to moisture, unwanted noise signals become generated across its exposed electric contacts, and in the extreme case, these contacts become grounded. Such unwanted noise signals combine with the desired detected output signals from the geophones to give an undesirable high noise-to-signal ratio.
An improved double-ended, single O-ring hybrid takeout clip is disclosed in my copending patent application, Ser. No. 310,387, and now U.S. Pat. No. 4,445,741.
This improved hybrid takeout clip has at one end a solid male plug provided with a single O-ring, and a tubular female plug provided with a single groove for accepting the male plug with its O-ring.
Also, a single-ended solid cylindrical male connector, having a pair of equal diameter O-rings around the cylindrical body portion of the male plug, and a single tubular female connector, having a pair of equal diameter inner annular grooves in the tubular female plug, are also known in the seismic art. The body portions of these single plugs are dimensioned to allow, in use, the tubular female plug to snugly accept therein the male plug, whereby the two grooves frictionally and consecutively receive the two O-rings for protecting the interconnected electric contacts of the male and female plugs against moisture penetration between and disconnection of the plugs.
While the two equal-diameter O-rings provide greater protection against moisture penetration and disconnection, a connector using them does have known drawbacks: (1) the male and female plugs are difficult to align prior to coupling; the two O-rings become seated consecutively within their grooves, and in so doing they tend to bind the tubular body portion of the female plug thus creating excessive frictional engagement which requires a strong force to complete the coupling the male and female plugs.